Jerry Jones attributed the decision to release fifth-round pick Danny Coale to two things: his lack of opportunity due to injury and the depth of the receiving corps.

Coale missed all of the offseason workouts and much of training camp because of a broken foot suffered during rookie minicamp that required surgery. He also missed some time during camp with a sore quadriceps and played in only two preseason games.

“He just hasn’t had enough time to really establish (himself) in a position that we really have numbers in,” Jones said of Coale on KRLD-FM. “We’ve got good numbers there. That has something to do with it. It has something to do with it that he just wasn’t able to really establish himself in any way because he’s had every few reps.”

*The Cowboys have difficult decisions to make at running back. DeMarco Murray and Felix Jones are guaranteed roster spots. The Cowboys like Phillip Tanner as the No. 3 back. Lance Dunbar and Jamize Olawale, a couple of undrafted rookies out of North Texas, are not among the 21 players who have been informed of their releases.

“All of those North Texas guys have a special attribute,” Jones said. “We can use them all, yet you can’t keep them all. We know a little more about Tanner because of the year he had last year and what he is with his work ethic. To be very candid with you, it was not as damning to him to have lost his time as it would be with someone let’s say like a Coale or someone like that.”

*Jones hinted that Ryan Cook, the center/guard acquired from the Dolphins for a seventh-round pick, could eventually challenge Phil Costa for the starting job at center.

“This, really, in my mind, is done and was done for our depth,” Jones said. “Plus, he’s very capable because he’s started in several games in the NFL. He is very capable of competing. Hopefully, you’ll see him in a lot of games this year.”